SQL select rows with only a certain value in them

Question

I have a table as such

Col 1 Col 2 Col 3
1       A     1
2       A     2
3       B     1
4       C     1
5       C     2
6       D     1

How do I only get unique rows which have Col 3 = 1?

I want to get rows 3 and 6 (Col 2 = B and D respectively). I do not want A nor C since they have Col 3 = 2 as well.

I've tried something along the lines of:

select col 2 from table group by col 2 having count(col 3) = 1

But that only brings up Col 2 for results so I'm uncertain if Col 3 contents = 1 or not.

EDIT: Sorry guys maybe I've not worded my question clearly. I want to get all of the rows of Col 2 which contain only Col 3 = 1 AND ONLY 1.

So if I tried WHERE Col 3= 1, it would return 4 rows because A has 1. But since A also has a row where Col 3 = 2, I do not want that, same for C. From this example table, I would want the end result to only show 2 rows, B and D.

My example table is an example, I actually have about 5000 rows to filter through, otherwise I'd do as you guys have suggested :)

Answer 1

SELECT col2
FROM your_table
GROUP BY col2
HAVING MAX(col3) = 1 AND MIN(Col3) = 1

Or

SELECT a.col2 
FROM your_table a
WHERE a.col3=1 AND NOT EXISTS(SELECT *
                              FROM your_table b 
                              WHERE a.col2=b.col2 AND b.col3<>1)